WO2024253529A1 - Transducteur - Google Patents

Transducteur Download PDF

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Publication number
WO2024253529A1
WO2024253529A1 PCT/NL2024/050297 NL2024050297W WO2024253529A1 WO 2024253529 A1 WO2024253529 A1 WO 2024253529A1 NL 2024050297 W NL2024050297 W NL 2024050297W WO 2024253529 A1 WO2024253529 A1 WO 2024253529A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnetic field
diaphragm
transducer
coil
dynamic coil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/NL2024/050297
Other languages
English (en)
Inventor
Wouter DIEDEREN
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lorentz Audio BV
Original Assignee
Lorentz Audio BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lorentz Audio BV filed Critical Lorentz Audio BV
Publication of WO2024253529A1 publication Critical patent/WO2024253529A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R13/00—Transducers having an acoustic diaphragm of magnetisable material directly co-acting with electromagnet
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2207/00—Details of diaphragms or cones for electromechanical transducers or their suspension covered by H04R7/00 but not provided for in H04R7/00 or in H04R2307/00
    • H04R2207/021—Diaphragm extensions, not necessarily integrally formed, e.g. skirts, rims, flanges
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2231/00—Details of apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor covered by H04R31/00, not provided for in its subgroups
    • H04R2231/003—Manufacturing aspects of the outer suspension of loudspeaker or microphone diaphragms or of their connecting aspects to said diaphragms
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2307/00—Details of diaphragms or cones for electromechanical transducers, their suspension or their manufacture covered by H04R7/00 or H04R31/003, not provided for in any of its subgroups
    • H04R2307/201—Damping aspects of the outer suspension of loudspeaker diaphragms by addition of additional damping means
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2307/00—Details of diaphragms or cones for electromechanical transducers, their suspension or their manufacture covered by H04R7/00 or H04R31/003, not provided for in any of its subgroups
    • H04R2307/207—Shape aspects of the outer suspension of loudspeaker diaphragms
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R2400/00—Loudspeakers
    • H04R2400/01—Transducers used as a loudspeaker to generate sound aswell as a microphone to detect sound
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H04R7/122—Non-planar diaphragms or cones comprising a plurality of sections or layers

Definitions

  • the present disclosure relates to electroacoustic transducers.
  • the most commonly known exemplary embodiments of such electro-acoustic transducers are loudspeakers and microphones, to which the present disclosure also relates.
  • the present disclosure relates to a device, such as an electronic device like a TV or a mobile device, comprising at least one such transducer.
  • electroacoustic transducer refers to transduction of energy, such as carried in an signal, in one of two ways: from an electrical signal to an acoustic signal (a loudspeaker) and/or from an acoustic signal to an electrical signal (a microphone).
  • the signal may be defined in either a time or frequency domain. If expressed in the frequency domain, a signal may comprise multiple frequency bands. For example, a signal may comprise a bass frequency band of lower signal frequencies, a mid-range frequency band of intermediate frequencies and a treble frequency band of higher frequencies. Generally, several electroacoustic transducers are combined to cover a frequency range that spans multiple frequency bands.
  • Electroacoustic transducers acting as microphones generally operate on the principle of electromagnetic induction and include a dynamic coil that is attached to or embedded in a diaphragm and arranged in a static magnetic field.
  • the diaphragm is excited to vibrate by acoustic waves and causes the dynamic coil to vibrate within a static magnetic field produced by a permanent magnet.
  • an electrical signal can be applied to the dynamic coil in order to generate an alternating magnetic field which interacts with the static magnetic field to excite motion in or of the diaphragm and thereby produce sound waves.
  • the diaphragm of conventional electroacoustic transducers emits or collects sound waves over its entire surface area while the dynamic coil is attached to a small part or even single point of the diaphragm.
  • the diaphragm has the shape of an end-opened cone and the dynamic coil is attached to said cone on a perimeter at its smaller opened end, and in conventional microphones, the center of a circular diaphragm is attached to the dynamic coil.
  • Transducers according to the prior art comprise a diaphragm, and at least one dynamic coil mechanically coupled to the diaphragm.
  • the dynamic coil is connected to a controller for the dynamic coil to receive or provide electrical signals comprising sound information.
  • at least one static magnetic field generator is provided in order to generate sound with the diaphragm or an electrical signal induced in the dynamic coil.
  • KR-20-0396654 discloses a loudspeaker with a helical dynamic coil winding around the permanent magnet coaxially with the N-S axis of the magnet.
  • This known speaker comprises a magnetic field absorber behind the magnet relative to the diaphragm, so as to reduce flux leakage and an associated phenomenon of attraction of iron-containing hemoglobin, which may cause migraines as well as brain and ear fatigue.
  • US-2012/114166 and US-2006/182304 discloses a speaker with a helical dynamic coil attached to a diaphragm and extending into the interior of an annular permanent magnet.
  • a shield cover may be arranged, also to reduce flux leakage.
  • a magnetic field shield arranged opposite the diaphragm relative to the magnetic field generator and parallel to the spiral shaped dynamic coil, where the magnetic field of the magnetic field generator is concentrated by the magnetic field shield on the dynamic coil embedded in or attached to the diaphragm.
  • the magnetic field shield can be a magnetic field guide.
  • the magnetic field generator may have small dimensions in comparison to the circumference of the dynamic coil embedded in or attached on the diaphragm.
  • the magnetic field shield may have dimensions at least approximately the size of the dynamic coil embedded in or attached on the diaphragm.
  • the magnetic field shield may comprise a metal plate.
  • the magnetic field shield may be designed in relation to a strength of the magnetic field from the static magnetic field generator to approximate magnetic saturation of the magnetic field shield.
  • a circumferential shape and a thickness of the metal plate may be configured to approximate magnetic saturation of the magnetic field shield.
  • the magnetic field shield comprises at least one ferromagnetic metal from a group, comprising: iron, nickel, cobalt, and further comprising magnetite, gadolinium, awaruite and permalloy, as well as alloys thereof.
  • the magnetic field shield and the magnetic field generator are mechanically connected.
  • a plurality of static magnetic field generators may be arranged in an at least approximately rotation symmetric fashion, relative to an axis running through a center of and at least locally perpendicular to the diaphragm.
  • the magnetic field shield may comprise at least one air flow passage.
  • the diaphragm may have a circumferential shape from a group of shapes comprising rectangular and more in particular square, and ellipsoid and more in particular round.
  • the spiral shaped dynamic coil which is embedded in or attached on the diaphragm, extends essentially perpendicular to the N-S axis of the static magnetic field generator.
  • the present disclosure relates to the above transducer, and also to a loudspeaker, a microphone and an electronic device each comprising such a transducer.
  • Figure 1 schematically depicts a cross section of a conventional electroacoustic transducer in the form of a loudspeaker for ease of reference;
  • Figure 2 schematically depicts an embodiment of an electroacoustic transducer according to the prior art disclosure in WO2021194339;
  • Figure 3 schematically depicts a perspective view of a prior art electroacoustic transducer with a planar diaphragm
  • Figure 4 schematically depicts planar views of diaphragms with various arrangements of multiple dynamic coils
  • FIG. 5 and 6 schematically depict embodiments of a suspension
  • Figures 7A and 7B depict augmenting frontal and sideway views of an embodiment of the present disclosure
  • Figures 8 and 9 exhibit improvement over a prior art configuration in figure 8 by a configuration according to the present disclosure in figure 9;
  • Figure 10 depicts an electronic device with therein implemented a transducer in accordance with the principles of the present disclosure
  • Figure 11 depicts an exploded view of an additional embodiment
  • Figure 12 depicts an embodiment of a magnetic field shield or guide.
  • FIG. 1 shows a conventional electroacoustic transducer, in particular a loudspeaker, in cross section through a plane containing a central axis thereof.
  • the illustrated conventional electroacoustic transducer has circular symmetry around its central axis.
  • the conventional loudspeaker has a diaphragm 2 in the form of an end-opened cone which is suspended by a suspension 7 that is in turn attached to a chassis 6.
  • a helical dynamic coil 3 is mechanically coupled to the diaphragm 2 at the center of the diaphragm 2 and magnetically coupled to a permanent static field magnet 5, by being arranged in an opening of the static field magnet 5. Electrical signals are supplied or received from the dynamic coil 3 by conventional means (not illustrated).
  • An alternating electrical signal may be supplied to the dynamic coil 3 to generate alternating magnetic fields which interact with the static field from the static field magnet 5 in order to convert the electrical signal to mechanical motion of the diaphragm 2, which results in an acoustic signal in a surrounding medium.
  • mechanical motion of the diaphragm 2 as a result of an acoustic signal moves the dynamic coil 3 within the static field and induces an electrical signal in the dynamic coil 2.
  • FIG. 2 shows an embodiment of an electroacoustic transducer 1 according to WO-
  • a dynamic coil 3 is mechanically coupled to the diaphragm 2.
  • the dynamic coil 3 is spiral and cone shaped and is arranged on or in at least a portion of the outer region 2.2 of the diaphragm 2.
  • the diaphragm 2 is illustrated as an end-opened cone, such as in conventional loudspeakers, though the diaphragm 2 may have various forms or shapes, such as conical, hemispherical, spherical, planar, circular, oval, rectangular, lobed and combinations thereof, each with or without openings. Examples are presented in this disclosure.
  • the function of the dynamic coil 3 is moving the diaphragm 2 by creating an alternating magnetic field according to the supplied electrical signal.
  • the mechanical coupling between the dynamic coil 3 and diaphragm 2 causes the diaphragm 2 to vibrate, thus producing sound waves.
  • the dynamic coil 3 consists out of an electrical conductor in the form of a wire. The number of rotations of the dynamic coil 3 dependents on the density of the material of the diaphragm 2, the area of the diaphragm 2 and the density of the electrical conductor.
  • the electroacoustic transducer 1 of FIG. 2 further comprises a static field magnet 5, which may be a permanent magnet and/or an electromagnetic coil.
  • the static field magnet 5 is a static field coil 5.
  • the static field magnet 5 may be arranged at different positions, for example within or around the cone-shaped diaphragm which results in a thinner construction.
  • the illustrated electroacoustic transducer 1 further comprises a chassis 6. However, the suspension 7 present in conventional electroacoustic transducers is made redundant.
  • the function of the static field magnet or coil 5 is to create a static magnetic field which opposes the magnetic field of the dynamic coil 3.
  • the static field coil 5 consists out of an electrical conductor in the form of a wire.
  • the properties of the static field coil 5 may be the same as the properties of the dynamic coil 3 but can also differ. It is further noted that the dynamic coil 3 and/or the static field coil 5 may exist out of multiple parts to limit inductance of said coils.
  • the electroacoustic transducer 1 of FIG. 2 is particularly suited to serve as a loudspeaker 8, though is not limited to this function. For example, it can also function as a microphone.
  • the illustrated example is deliberately presented in the form of a conventional loudspeaker to show implementation within existing systems.
  • a conventional voice coil arranged within an opening of the static field magnet 5 is replaced by the dynamic coil 3 arranged on or in at least a portion of the outer region 2.2 of a replacing diaphragm 2.
  • diaphragm 2 In the function of a loudspeaker with an open-ended cone shaped diaphragm 2, a dynamic coil 3, a static field magnet 5 and a chassis 6, diaphragm 2 is actuated by movement of the dynamic coil 3 relative to the static field magnet or coil 5.
  • the dynamic coil 3 In FIG. 1, the dynamic coil 3 is arranged in a center region of the diaphragm 2, while in FIG. 2, the dynamic coil 3 is arranged on at least a portion of an outer region of the diaphragm 2. Because of the arrangement illustrated in FIG. 2, the dynamic coil 3 actuates the diaphragm 2 over at least a portion of its outer region, in contrast to the center region of the conventional loudspeaker of FIG.
  • the diaphragm 2 of FIG. 1 needs to be stiff, damping and low in mass to propagate sound waves through the diaphragm 2 faithfully. Moreover, a flexible suspension 7 is required. However, in FIG. 2, the diaphragm 2 need not be stiff to transfer force through the entire cone to obtain faithful sound production and no flexible suspension 7 is needed. Choice of materials is therefore increased, construction is simplified and quality of sound production is improved. [045] The above argument equally applies to an electroacoustic transducer 1 in the function of a microphone, in which sound waves through air impinge on diaphragm 2 and are collected rather than produced. A stiff diaphragm 2 is no longer required and thus no longer limiting design of electroacoustic transducers 1.
  • FIG. 3 shows another prior art embodiment of an electroacoustic transducer 1 wherein the diaphragm 2 is substantially planar.
  • the substantially planar diaphragm 2 reduces a thickness of the electroacoustic transducer 1 compared to conventional electroacoustic transducers, such as illustrated in FIG. 1 and FIG. 2.
  • a static field magnet 5 is provided and may be a permanent magnet and/or electromagnet. The top of the magnet may define a North pole and the bottom of the magnet 5 in Fig. 3 may be a South pole, or vice versa.
  • the electroacoustic transducer 1 of FIG. 3 is particularly suited to serve as a microphone, or as a loudspeaker 8.
  • the coil 5 may be arranged parallel to the diaphragm 2, further contributing to the small dimensions of the resulting transducer 1.
  • the static field coil 5 may advantageously be wound in a plane, such as in a spiral, and/or may be fixed in space relative to the dynamic coil 3, which is wound in a flat spiral 3 to facilitate mechanical connection with or on, or incorporation in the diaphragm 2.
  • Such a prior art embodiment constitutes an advantageously improved electroacoustic transducer 1 comprising two coils 3, 5, namely a dynamic coil 3 and a static field coil 5, that are positioned in a stacked manner with a small distance between the coils 3, 5.
  • the dynamic coil 3 is incorporated in the diaphragm 2 and thus mechanically coupled to the diaphragm 2.
  • the dynamic coil 3 acts as a receiving coil or a voice coil while the static field coil 5 produces a static magnetic field.
  • An electrical audio signal applied to both coils 3, 5 via input or output terminal 4 creates interacting magnetic fields which cause the two coils 3, 5 to attract or repel each other according to the applied electrical signal.
  • the mechanical coupling between the dynamic coil 3 and the diaphragm 2 forces the diaphragm 2 to start vibrating and hence produce sound waves according to the applied electrical signal.
  • the use of two flat coils 3, 5 results in an even thinner electroacoustic transducer which may thus be integrated in various other systems more easily.
  • the electroacoustic transducer 1 of any embodiment may comprise at least one magnet or static field coil 5 configured to electromagnetically interact with the dynamic coil 3. Where multiple flat, spiral shaped dynamic coils 3 are employed, as in FIG. 4, an equal number of static field coils 5 may be deployed or even be preferred.
  • the multiple static field coils 5 are then preferably arranged in a similar geometry as the multiple dynamic coils 3, preferably in parallel thereto. The configuration with multiple dynamic coils 3 and/or multiple static field coils 5 is further addressed in relation to figures 4.
  • FIG. 10 shows an example of integration of the electroacoustic transducer 1 in an electronic device 10.
  • the electronic device 10 is a TV, in which a signal source is provided as a controller 11 internally for supplying electrical signals to transducer 1 in the form of a loudspeaker 8 which is provided at an outer surface of a housing of the electronic device 10, in order to emit sounds.
  • the device 10 could be a mobile device with a microphone and a processor forming the controller 11 to process electrical signal from and induced in the dynamic coil 3.
  • the electronic device 10 comprises the controller 11, that may be connected to the electroacoustic transducer 1 via the above described input or output terminals 4 and is configured to provide or received electrical signals to or from the dynamic coil 3 and the static field coil 5.
  • Both a TV and most mobile devices have a screen 17, sometimes a touch screen, but the present disclosure may equally relate to a electronic devices without a screen 17.
  • the electronic device 10 has an advantage that it can be fully enclosed with respect to the environment also at the transducer 1 because the diaphragm 2 of the electroacoustic transducer 1 mounted in the electronic device 10 seals an opening in the electronic device 10 in which the electroacoustic transducer 1 is mounted.
  • the electronic device 10 with the electroacoustic transducer 1 is better sealed and may even be waterproof and/or gas proof.
  • electronic devices 10 may also be made smaller because less space is required for electroacoustic transducers 1 due to their reduced thickness compared to conventional electroacoustic transducers.
  • the electroacoustic transducer 1 may be used as a microphone and/or a loudspeaker 8 and may additionally be switched between those functions, for example by the controller 11, so that a separate microphone and a separate loudspeaker 8 are not needed and a single electroacoustic transducer 1 can be used to perform both functions.
  • FIG. 4 shows planar views of diaphragms 2 with multiple dynamic coils 3.
  • the multiple flat, spiral shaped dynamic coils 3 are arranged on or in the flat diaphragm 2.
  • Each dynamic coil 3 is preferably associated with an acoustic frequency band. This can be achieved, for example, by supplying or receiving electrical signals to each dynamic coil 3 separately, using a single controller 11 or multiple controllers 11.
  • Each of the multiple dynamic coils 3 may be electrically connected to an input or output terminal 4 of the controller 11. Jointly, the multiple dynamic coils 3 may thus cover a selected acoustic frequency spectrum faithfully.
  • the electroacoustic transducer 1 may cover a wider frequency range. Furthermore, combinations of multiple electroacoustic transducers (one for each sub-divided acoustic frequency band), as is conventionally the case, may be avoided and a single electroacoustic transducer 1 may be employed to cover similar frequency bands with one device. [057] In FIG. 4, a circular diaphragm 6 is illustrated with three flat (or planar) and spiral shaped dynamic coils 3, labelled 3.1, 3.2 and 3.3.
  • the coils 3.1, 3.2, 3.3 are concentrically arranged and each is electrically connected to a separate input or output terminal 4, labelled 4.1, 4.2 and 4.3 corresponding to their respective coils 3. 1 , 3.2, 3.3.
  • the dynamic coil 3.1 may be a bass coil 3.1
  • the dynamic coil 3.2 may be a mid-range coil 3.2
  • the dynamic coil 3.3 may be a treble coil 3.3 so that the bass coil 3.1, the mid-range coil 3.2 and the treble coil 3.3 are arranged in order of acoustic frequency band with the treble coil 3.3 with the highest acoustic frequency band arranged nearest or at the central region of the diaphragm 2.
  • the dynamic coils 3 are arranged over the diaphragm 2 at a radial offset or spacing with respect to each other.
  • each input terminal 4. 1, 4.2, 4.3 receives its own audio supply from controller 11, which higher frequency signals are filtered out according to the frequency band of each of the multiple dynamic coils 3.1, 3.2, 3.3.
  • the input terminal 4.3 supplies lower acoustic frequencies than the input terminal 4.2 to the mid-range coil 3.2.
  • the input terminal 4.2 supplies lower acoustic frequencies to the mid-range coil 3.2 than the input terminal 4. 1 to the treble coil 3.1.
  • the larger a dynamic coil 3.1, 3.2, 3.3 the lower the frequency band supplied to it. Though this arrangement is preferred, other orders and two or four or more dynamic coils 3 may be considered.
  • FIG. 4 interpreted as a loudspeaker
  • the dynamic coil 3 is split into multiple dynamic coils 3, each associated with an acoustic frequency band.
  • the plurality of coils making up the dynamic coil 3 need not be arranged concentrically, and may be dispersed over an area of a diaphragm 2 having a large enough surface to accommodate such multiple dynamic coils 3.
  • FIG. 4 is disclosed as an embodiment having the diaphragm 2 with multiple dynamic coils 3.
  • such configurations may also relate to arrangements of multiple static field coils or magnets 5 that may be combined with corresponding diaphragms 2 and multiple dynamic coils 3.
  • FIGS. 5 and 6 show an advantageous suspension 7 for a diaphragm 2.
  • the suspension is configured to improve acoustic insulation of the diaphragm 2 from attached structures.
  • the structure of the suspension 7 may be provided by arranging slits in a membrane 9 around the actual diaphragm 2 within which the flat, spiral shaped dynamic coil 3 is arranged.
  • the suspension 7 may thus be integral with the diaphragm 2.
  • the suspension 7 of the illustrated embodiment may be provided as a distinct component.
  • the slits are configured to reduce transfer of mechanical vibrations across the suspension 7 by defining a tortuous path of mechanical connectivity between components internally and externally coupled to the suspension 7 (e.g. the diaphragm 2 and the chassis 6).
  • the suspension 7 comprises inner angular slits 7.1, outer angular slits 7.2 and radial slits 7.3.
  • the terms angular and radial indicate directions relative to the center of a plane or space enclosed by the suspension 7 (e.g. the diaphragm 2), in which the dynamic coil 3 is arranged.
  • the inner and outer angular slits 7.1, 7.2 partly overlap in angular direction but are spaced apart in radial direction.
  • the radial slits 7.3 are connected to the inner angular slits 7.
  • angular slits 7.1, 7.2 are illustrated as concentric circle segments, other shapes are possible such as elliptical, linear and angled forms.
  • the radial slits 7.3 may also be implemented with angular components.
  • Various alternative arrangements of the slits 7.1, 7.2, 7.3 are thus conceivable.
  • the suspension 7 of FIGS. 5 and 6 thus provides mechanical integrity yet improves acoustic insulation of the plane or space enclosed by the suspension 7 (e.g. the diaphragm 2) and adjacent structures (e.g. the chassis 6 or the electronic device 10).
  • the slits 7.1, 7.2, 7.3 may thus define the suspension 7, while the diaphragm 2 may in turn be delineated by the suspension 7.
  • the suspension 7 may be provided in a flat object, such as a face of an electronic device 10, and define the diaphragm 2 as the part enclosed by the suspension 7, e.g. as shown in FIG. 13.
  • the slit structure defining the suspension 7 may thus be employed with known electroacoustic transducers as well as with the electroacoustic transducer 1.
  • the diaphragm 2 of any embodiment is preferably elastic in the acoustic frequency bands associated with the multiple dynamic coils 3.1, 3.2, 3.3 or at least the frequency band of the dynamic coil 3 where only one dynamic coil 3 is present.
  • the diaphragm 2 comprises at least one material from a group, the group comprising a rubber-like material, rubber, silicone, polyimide, polyamide, polyester resin and polycarbonate, preferably reinforced with carbon and / or glass fibres.
  • the materials from this group possess sufficient flexibility to conform to local deformation due to impinging sound waves and/or to actuation by the one or multiple dynamic coil(s) 3.
  • the diaphragm 2 is composed of a non-stiff material, preferably with a Young’s modulus between 0.1 GPa and 2.4 GPa. In tests of an electroacoustic transducer according to an embodiment, these materials and this range was found to provide effective transduction of electrical signals to acoustic signals.
  • FIG. 7 depicts an embodiment of the present disclosure in a frontal view in FIG. 7A and a side view in FIG. 7B.
  • the diaphragm 2 has a rectangular and more in particular a square circumference, and is mounted in a square chassis 6 via suspension 7.
  • windings of flat, spiral shaped dynamic field coil 3 are embedded in diaphragm 2, but may alternatively be arranged on a surface of diaphragm 2.
  • Static field coil or magnet 5 is, in the view of FIG. 7B, arranged under the diaphragm 2.
  • a thickness of the static field coil or magnet (in a direction perpendicular to the diaphragm and also in the N-S direction of static coil or magnet 5) is preferably minimized.
  • a sufficient magnetic field strength / flux is required from the static field coil or magnet 5 at the diaphragm or at least the dynamic coil 3 thereon or therein, which may be compromised if the static field coil or magnet 5 is too small.
  • Increasing a width of the static field coil or magnet 5 (perpendicular to the N-S orientation) aggravates this concern. Therefore, the configuration of FIG. 3 with a very wide static field coil or magnet 5 and short N-S length is not very good.
  • FIG. 8 depicts an exemplary view of magnetic field lines from a static field coil or magnet 5 set-up at the diaphragm 2 in a possible configuration.
  • a magnetic field shield 12 is additionally provided.
  • the magnetic field shield 12 is essentially flat (or planar) and arranged opposite the diaphragm 2, relative to the static field coil or magnet 5, so that the static field coil or magnet 5 is placed between the diaphragm 2 and the magnetic field shield 12, while the shield 12 is essentially parallel to the flat, spiral shaped dynamic coil 3.
  • the magnetic field shield 12 has dimensions that at least approximately the size and shape of the diaphragm 2. In the shown embodiment of FIG. 7B, the magnetic field shield 12 is even bigger than the diaphragm 2 and corresponds in size and form with the chassis 6.
  • FIG. 9 exhibits the effects of providing the magnetic field shield 12.
  • Magnetic field lines on the side of the magnetic field shield 12, opposite the side with the diaphragm 2 and the spiral shaped dynamic coil 3, are suppressed, in that the magnetic field shield 12 acts as a conduit for magnetic field lines, and magnetic field lines on the side of the diaphragm 2 with the spiral shaped dynamic coil 3 thereon or therein have a higher density / flux.
  • the field lines are better homogenized in FIG. 9, than in FIG. 8 that represents a configuration without the magnetic field shield 12.
  • the flat (or planar) diaphragm 2 and the spiral shaped dynamic coil 3 incorporated therein or arranged thereon extend essentially perpendicular to the N-S axis of the magnet 5, with the flat (or planar) magnetic field shield parallel to the diaphragm 2 and the coil 3.
  • This allows for a synergetic effect that the more concentrated magnetic flux has an increased effect on a larger portion of the surface area covered by the dynamic coil 3, much more so than when the dynamic coil 3 were helical with a central axis in line with the N-S axis of the magnet 5 (as in the above acknowledged prior art), which would only have an end of such a helical coil in the enhanced magnetic field.
  • the magnetic field shield 12 can be considered to enhance field strength and flux, and to improve homogeneity of the field at the spiral shaped dynamic coil 3 on or in the diaphragm 2. This is in particular realized under the following circumstances (to which the scope of the present disclosure is not necessarily limited).
  • the magnetic field shield 12 comprises a metal plate, in the embodiment shown in
  • the magnetic field shield 12 is made from a ferromagnetic metal.
  • a ferromagnetic metal can be one of: iron, nickel, cobalt. Less common, but not excluded, would be the use of at least one of magnetite, gadolinium, awaruite and permalloy. Naturally, it’s well known to the skilled reader, that alloys of ferromagnetic materials also function for guiding magnetic fields. Therefore, the magnetic field shield could equally be referred to as a magnetic field guide.
  • the magnetic field shield 12 is designed, in relation to a strength of the magnetic field from the static field coil or magnet 5, to approximate magnetic saturation of the magnetic field shield 12. Saturation is the state reached by the magnetic field shield when an increase in applied external magnetic field does not yield a further increase in the magnetization of the material.
  • a circumferential shape and a thickness of the metal plate are configured to approximate magnetic saturation of the magnetic field shield.
  • the magnetic field shield 12 and the static field coil or magnet 5 are mechanically connected.
  • this improves magnetic coupling of the magnetic field from the static field coil or magnet 5 into the magnetic field shield 12.
  • a magnetic field shield 12 is depicted.
  • a permanent magnet embodying the static magnetic coil or magnet 5 is arranged.
  • the permanent magnet could be replaced by one or more than one static field coil.
  • the magnet 5 may be fixed to the magnetic field shield 12.
  • For magnetic decoupling magnet 5 may nevertheless be held at a distance with a gap in between magnet 5 and magnetic field shield 12.
  • the magnetic field shield 12 in the form of a square plate comprises at least one air flow passage 16, so as not to hamper air pressure waves.
  • the air flow passages 16 extend radially, but these can extend circularly or even concentrically or spiraling.
  • Four air passages 16 are arranged in the magnetic field shield 12, but a lower or higher number of air passages 16 may be provided.
  • there’s a trade of between a need for air passages and the amount thereof to maintain high quality sound generation / capture on the one hand, and on the other hand the mass and surface of ferromagnetic material to form an effective magnetic field shield 12.
  • the magnetic field shield 12 has another circumferential form than square, like oval or rectangular or any other shape, other shapes of air passages 16 may be deployed than the one shown in FIG. 12.
  • a plurality of air flow passages is provided. If so, then these are preferably arranged in an at least approximately rotation symmetric fashion, relative to an axis running through a center of and at least locally perpendicular to the diaphragm, for similar considerations as those in play for arrangement of a plurality of magnets 5 or coils 13, 14.
  • a conus shaped diaphragm 2 and a single static field magnet 5 are disclosed, which may be augmented in accordance with the present disclosure, using a magnetic field shield 12, for example a conus shaped magnetic field shield 12.
  • a round, planar diaphragm 2 and two static field coils 5 formed by cores 13 and windings 14 are disclosed in another combination.
  • Dynamic coil 3 is not shown in FIG. 11, but is in fact arranged on or integrated in flat diaphragm 2,
  • a conus (or pyramid) shaped, or round or rectangular planar diaphragm 2 may be accompanied by one, two or more static field magnets 5 of FIG. 7 and/or one, two or more static field coils 13, 14 of FIG. 11.
  • a rectangular (square) diaphragm 2 of FIG. 7 may be combined with a single or more than one static field magnet 5 or one or more than one static field coil 13, 14, either being associated with the magnetic field shield 12.
  • bus or cylinder shaped protrusions 13 are formed extending from the magnetic field shield 12.
  • coils 14 may be wound to form static field coils 5, when connected to a controller 11 supplying a signal having a constant frequency.
  • bus or cylinder shaped protrusions may also be made of ferromagnetic metal.
  • a loudspeaker 8 may comprise an electroacoustic transducer 1, where examples are illustrated in the figures and discussed herein above.
  • a loudspeaker 8 comprises an electroacoustic transducer 1
  • the dynamic coil 3 is configured as a voice coil which receives an electrical signal and is configured to transduce the electrical signal into an acoustic signal upon electromagnetic interaction with a static field magnet 5.
  • the static field magnet 5 can be a permanent magnet or an electromagnet, such as the static field coil 5 of preferred embodiments of the disclosed electroacoustic transducer 1.
  • a microphone may comprise an electroacoustic transducer 1, where examples are illustrated in the figures and discussed herein above. Although a microphone could be referred as an acoustoelectric transducer, for the purpose of the present disclosure, herein all transducers for generating sound from electrical signals and vice versa are designated as ‘electroacoustic’ transducers.
  • the dynamic coil 3 is configured to receive an acoustic signal and transduce the acoustic signal into an electrical signal upon electromagnetic interaction with a static field magnet 5.
  • the static field magnet 5 can be a permanent magnet or an electromagnet, such as the static field coil 5 of preferred embodiments of the disclosed electroacoustic transducer.
  • An electronic device 10 may comprise an electroacoustic transducer 1. Examples are illustrated in the figures, particularly in FIG. 10.
  • the electroacoustic transducer 1 can be configured to act as a loudspeaker 8 and/or microphone in distinct or similar frequency bands.
  • the diaphragm 2 is planar and holes are absent, thus providing an electroacoustic transducer 1 which may advantageously seal an opening in the electronic device 10 arranged to receive the electroacoustic transducer 1.
  • a chassis may be provided with a static field magnet 5 and/or the static field magnet 5 may be at least one static field coil 5.
  • the dynamic coil 3 or the multiple dynamic coils 3, 3.1, 3.2, 3.3 may each be electrically connectable or connected to an input or output terminal 4, 4.1, 4.2, 4.3 of controller 11.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)

Abstract

La présente invention concerne des transducteurs, en particulier des transducteurs électroacoustiques et des transducteurs acousto-électriques. De tels transducteurs comprennent une membrane sensiblement plane, et au moins une bobine dynamique en forme de spirale incorporée dans la membrane ou fixée mécaniquement sur celle-ci. La bobine dynamique est connectée à un dispositif de commande pour la bobine dynamique pour recevoir ou fournir des signaux électriques comprenant des informations sonores. Afin de générer un son avec la membrane ou un signal électrique induit dans la bobine dynamique, au moins un générateur de champ magnétique statique est fourni. La présente invention concerne en outre un blindage de champ magnétique disposé à l'opposé de la membrane par rapport au générateur de champ magnétique et parallèle à la bobine dynamique en forme de spirale, le champ magnétique du générateur de champ magnétique étant concentré par le blindage de champ magnétique sur la bobine dynamique incorporée dans la membrane ou fixée sur celle-ci. Ainsi, un flux magnétique plus concentré et potentiellement plus homogène ou optimisé/augmenté est créé au niveau de la bobine dynamique sur ou dans la membrane.
PCT/NL2024/050297 2023-06-07 2024-06-06 Transducteur Ceased WO2024253529A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL2035027 2023-06-07
NL2035027 2023-06-07

Publications (1)

Publication Number Publication Date
WO2024253529A1 true WO2024253529A1 (fr) 2024-12-12

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Application Number Title Priority Date Filing Date
PCT/NL2024/050297 Ceased WO2024253529A1 (fr) 2023-06-07 2024-06-06 Transducteur

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WO (1) WO2024253529A1 (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1158835A2 (fr) * 2000-05-22 2001-11-28 The Furukawa Electric Co., Ltd. Dispositif transducteur acoustique plan
EP1194001A1 (fr) * 1999-06-11 2002-04-03 FPS Inc. Transducteur acoustique plan
KR200396654Y1 (ko) 2005-07-13 2005-09-23 (주)대성인터내셔널 피로 감소를 위한 소형 스피커 유닛
US20050220320A1 (en) * 2004-03-30 2005-10-06 Kim Kyung-Tae Speaker for mobile terminals and manufacturing method thereof
US20060182304A1 (en) 2004-03-11 2006-08-17 Tomoyasu Takase Speaker, module employing it, electronic apparatus and device
US20120114166A1 (en) 2006-01-24 2012-05-10 Panasonic Corporation Speaker and electronic apparatus and device using the same
WO2021194339A1 (fr) 2020-03-25 2021-09-30 Lorentz Audio B.V. Transducteur électroacoustique et haut-parleur, microphone et dispositif électronique comprenant ledit transducteur électroacoustique

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1194001A1 (fr) * 1999-06-11 2002-04-03 FPS Inc. Transducteur acoustique plan
EP1158835A2 (fr) * 2000-05-22 2001-11-28 The Furukawa Electric Co., Ltd. Dispositif transducteur acoustique plan
US20060182304A1 (en) 2004-03-11 2006-08-17 Tomoyasu Takase Speaker, module employing it, electronic apparatus and device
US20050220320A1 (en) * 2004-03-30 2005-10-06 Kim Kyung-Tae Speaker for mobile terminals and manufacturing method thereof
KR200396654Y1 (ko) 2005-07-13 2005-09-23 (주)대성인터내셔널 피로 감소를 위한 소형 스피커 유닛
US20120114166A1 (en) 2006-01-24 2012-05-10 Panasonic Corporation Speaker and electronic apparatus and device using the same
WO2021194339A1 (fr) 2020-03-25 2021-09-30 Lorentz Audio B.V. Transducteur électroacoustique et haut-parleur, microphone et dispositif électronique comprenant ledit transducteur électroacoustique

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